Mold material?

[Gerhard Gerber]

Hi All

Just had a bit of a brainwave....

I want to make molds of my BK2's scales and then stuff the molds with resin and bits of material to make camo Micarta like that YT video some might have seen.

Any tips on something really commonly available I could use to make the molds?

[hiraethus]

Note - I've never done this so am guessing here.

You'll need something that is stiff and strong so you can compress the fabric and resin as it's drying to get the air out, plus some kind of release agent/lubricant that won't react with the epoxy.  I've seen flat micarta made with wooden presses and waxed paper to stop it sticking.

Plaster of Paris might work for the moulds, but may be too brittle.  Maybe reinforce it with some fibrous material (glass fibre)?  You'll probably want to make the scales slightly oversized if possible too, so you can sand back to a good finish.

[Sparky415]

  
Wrap the BK in cling film then wrap in micarta to make a mold?

Or try making a wood negative mold, lining it with two layers of cling film, probably wax as well   

[Crow]

Clay might work, if it needs to be hard.

Plaster, if not needed to use mold again.

[Dr Hunt]

Plaster is a common material for low use count. Art and design supplies shops often have the stuff needed to make a plaster mould.

[Gerhard Gerber]

Note - I've never done this so am guessing here.

You'll need something that is stiff and strong so you can compress the fabric and resin as it's drying to get the air out, plus some kind of release agent/lubricant that won't react with the epoxy.  I've seen flat micarta made with wooden presses and waxed paper to stop it sticking.

Plaster of Paris might work for the moulds, but may be too brittle.  Maybe reinforce it with some fibrous material (glass fibre)?  You'll probably want to make the scales slightly oversized if possible too, so you can sand back to a good finish.

Thanks, most votes for Plaster of Paris.
You mention my main concern, strength when compressing it......and give a simple solution - I'm pretty sure it would be strong enough if I construct the mold like a leg cast, everything is cheap and easily available! 
Just didn't think that far 
Thanks 

[hiraethus]

 

Remember, we need pics.

[Dr Hunt]

Note - I've never done this so am guessing here.

You'll need something that is stiff and strong so you can compress the fabric and resin as it's drying to get the air out, plus some kind of release agent/lubricant that won't react with the epoxy.  I've seen flat micarta made with wooden presses and waxed paper to stop it sticking.

Plaster of Paris might work for the moulds, but may be too brittle.  Maybe reinforce it with some fibrous material (glass fibre)?  You'll probably want to make the scales slightly oversized if possible too, so you can sand back to a good finish.

Thanks, most votes for Plaster of Paris.
You mention my main concern, strength when compressing it......and give a simple solution - I'm pretty sure it would be strong enough if I construct the mold like a leg cast, everything is cheap and easily available! 
Just didn't think that far 
Thanks 

How about making the plaster mould with a big rectangular form? It is robust when fully dried and lays flat while you work on the scales casting.

[AimlessWanderer]

Sounds like you need something that's not just mouldable, but strong unber compression so that you can press them to force the resin through the fibres, and also squeeze out the excess.

Here's a thought which either might work, or might inspire a better idea from someone else...... sand casting type mould

Make a top and bottom wooden box, and fill with wet sand. You could try using a diluted water based glue for the liquid to help the sand retain it's form afterwards. Wrap the existing handles in cling film, and work them into the wet sand to the depth of the steel, remove the knife and allow the sand to dry. Maybe a coat of some sort of spray adhesive or fixative after drying might help strengthen it further. Fill both halves with the new material, and press them together with a piece of bar stock the same dimensions as the tang in between so it lips over a bit, and squeeze the box using g cramps with as much force as the box will take. The moulds might no survive to cast another pair, put it just means refilling the boxes with the sand mix.